Do-It-Yourself Don'ts

Every once in a while, we make a mistake. Then again, every so often we get treated to the experience of almost making a mistake--or, more frequently for avid readers of aviation safety, learning about an actual error that was made by someone else. The trick is turning that event into a learning experience.

When it comes to fueling an aircraft, we're talking about a potentially significant message. As a kid growing up on Long Island, every couple of months we'd go visit my Aunt Jeanette in the Bronx. I have many memories of our visits there, but the one I'm recalling now happened in the fall or winter, when the air was drier. To zap my kid brother, all I had to do was walk across her living room, and I could summon up a visible spark from my outstretched fingertip.

Could that sort of static electricity cause a problem when fueling an aircraft? At most of the places I fly, there's usually a line person with a fuel truck--and all the proper OSHA-sanctioned equipment--who dispenses what we all know is a flammable liquid at fire-hose speeds into whatever I've been flying. But every once in awhile I land somewhere to find only a pump-it-yourself operation. With these, you taxi up to the pumps, swipe a credit card, fill up, and fly away. According to a 2007 paper by the Airport Cooperative Research Program within the Transportation Research Board (sponsored by the FAA), about three-quarters of the FBOs that were surveyed provide fueling services. And about one in four of the fixed-base operators (FBOs) offers self-serve fueling.

Not all types of fuel lines are created equal, however. We've all gassed up our cars at the filling station without too much thought about stray sparks. We've probably all filled up a gas can for the lawn mower, too. Those rubber fuel hoses found at a typical gas station have metal or carbon/graphite lines for dissipation of static charges.

Even though it is a fluid, gasoline accumulates a static charge when it flows, and the faster it moves through the line the more charge that can build up. Aircraft fuel hoses are larger than their automotive counterparts, and aircraft fuel tanks are generally bigger, too, and can therefore build up even more electrical charge.

Whether you're gassing up the mower or the airplane, if you're doing it with jerry cans sitting in the back of a pickup truck on a plastic bed liner, or a carpeted floor, you're playing with fire. You're insulating the static charge, which may discharge to the grounded nozzle. Non-grounded plastic and (worse) metal containers have both been involved in a number of horrific accidents.

If you're not fueling it yourself:

• Make sure the line person is using some means of grounding.
• Do not remain in the airplane while it is being fueled.
• Stay upwind of (and to play it safe, stand well away from) the refueling operation.
• Make sure everything electrical aboard the aircraft has been turned off.

If you are doing it yourself:

• If that do-it-yourself pump has a grounding wire--according to fueling safety standards, it should--be sure to attach the grounding clip to your airplane, first. And it should be detached, last. (The line guys at my airport use the exhaust stack.)
• Ensure that the fuel nozzle is touching the fuel tank filler neck opening while you are filling it (to dissipate static charges from flowing fuel).
• Don't wear synthetic fabrics--they generate static. If you are in a fire, the fabric will melt and stick to your skin.
• Believe it or not, two of the most unhealthful hazards regarding potential bodily contact with avgas involve getting it on your skin or clothing, and breathing its vapors. If you accidentally spill avgas on an article of clothing, remove it. Immediately wash any part of your body that may have gotten splashed with it, using a waterless hand cleaner followed by soap and water. Never attempt to siphon avgas--it's not the accidental swallowing that could get you so much as the lung damage (chemical pneumonitis), if vomiting occurs or is induced. Also, alkyl lead is toxic if absorbed into the body by any means.
• Never fuel an aircraft while it is being preheated.
• Never fuel an aircraft while inside any building or structure. The National Fire Prevention Association recommends that aside from fuel farms, no more than five gallons of avgas should be stored in any airport building.
• Never conduct fueling operations while on a runway or taxiway.
• If you're refilling a portable container, place it on the ground, at a safe distance from your vehicle (aircraft or otherwise). Also, touch the container with the nozzle before removing the lid to fill it up. This gives any charge harmless access to the ground.

Always remember to:

• Turn all aircraft electrical devices off, and do not carry any lighters, matches, or other sources of ignition during fueling. Do not use a cell phone or radio while you're fueling.
• Keep a fire extinguisher at hand.
• Postpone or discontinue your fueling whenever lightning is observed in the vicinity.
• Maintain frequent visual checks during fueling to avoid overflows. Tip: Listen for the changing sound that signifies your tanks are getting--or are--almost full.
• Unless a hose with an approved nozzle is used, you should also be using a non-conductive funnel to lessen the chances of spillage.
• Don't smoke! The minimum recommended distance from fuel servicing operations for anyone smoking is 50 feet.
• Always ensure you're getting the proper grade of fuel, and sample its quality beforehand if there's any doubt.
• Know your aircraft's fuel system, especially if you're depending on having full tanks. Remember the effects of temperature on fuel volume. If you top off the tanks on a cool morning after you get back from a short flight, and then it warms up in the afternoon, you're going to lose fuel out the overflow vent, onto the ramp. The coefficient of volumetric expansion for avgas is about 0.00075 per Fahrenheit degree, so if you top off the tanks--let's take a 40-gallon fuel capacity as an example--and then the temperature goes up just 20 degrees, you'll lose more than a half-gallon of fuel (that is, if no one takes it flying again anytime soon).
• Last but not least, make sure those fuel tank caps are securely tightened after you're done.

Jeff Pardo is an aviation writer in Maryland with a commercial pilot certificate for airplanes, and instrument, helicopter, and glider ratings. He has logged about 1,300 hours since 1989. Pardo has also flown for the Civil Air Patrol.

Want to know more?
Links to additional resources about the topics discussed in this article are available at AOPA Flight Training Online.